Raw lamb kidney may have palatability and nutritional advantages as a cat food ingredient over other co-products. Researchers at Massey University observed distinct differences among cats’ preference for various raw organ meats and co-products from cows and lambs. Likewise, raw ingredients from lamb and beef had different palatability. Overall, cats preferred liver and kidney from both species of livestock. Comparing equivalent raw ingredients from either animal, the cats tended to prefer lamb over beef.
The journal Animals published the study, which examined palatability of raw lung, heart, kidney, tripe, liver and mechanically deboned meat (MDM) from lamb and beef. Eight domestic short-haired cats ate each of the six lamb and six beef components. The researchers used two-bowl acceptance and preference tests to develop palatability ranking of ingredients within and among species.
While liver was the most palatable raw ingredient in the test, the scientists pointed out limitations in the ingredients use. Since liver contains high amounts of vitamin A, pet food formulators need to avoid upper limits for the vitamin’s inclusion in pet food. The researchers wrote that lamb kidney is a viable, highly palatable and safer alternative to liver for high value pet food.
Cats preferred lamb over beef ingredients, except for heart and liver, which were equal between species. The researchers suggested that the age of the animals at slaughter may have influenced this. In New Zealand, lambs are butchered at typically 4 to 9 months old, while farmers cull cows at 5 to 8 years generally. Off-flavors may develop as the animals age, or the ingredients may become tougher with connective tissue.
Lamb palatability ranking
- Liver, Kidney
- Lung, Heart, Tripe
Beef palatability ranking
- Heart, Lung, Tripe
The researchers noted that the lamb and beef components they tested may have different rankings if they were cooked. They tested the ingredients raw to avoid the palatability influences of thermal processing. Also, their research involved a convenience sample of cats which were both intact and sterilized.
Vitamin A in pet food
Learn more about vitamin A as part of dog and cat diets in Ingredient Issues, a Petfood Industry column by Greg Aldrich, PhD, consultant and Kansas State University researcher: Vitamin A – a balancing act.
“In an age of extremes and absolutes, vitamin A serves as a potent example of the necessity of balance in diet and nutrition,” Aldrich wrote. “This is an important vitamin that has a direct effect on vision, the endocrine system in many ways and gene expression modulation. A deficiency can lead to blindness, skin lesions, reproductive issues and pneumonia, while an excess may result in anorexia, diarrhea, bone deformities and cancer. So, a more-is-better approach is as detrimental as having none at all…”